Gluten-free lunches get their own bag.

The gluten-free lunch needs a dedicated lunch box — one that never shares space with regular bread, crackers, or anything that crumbles.

Crumbs are the problem. You can’t just set the gluten-free sandwich next to the regular one in the same bag. Crumbs migrate. They settle in corners and touch the gluten-free food, and for someone with celiac or a serious sensitivity, even that tiny contact can cause a reaction. So treat the gluten-free lunch like its own protected zone.

The simplest fix is to dedicate a whole lunch bag or box to gluten-free food only. If you can’t do that, use a hard-sided container with a tight lid and keep it on the opposite side of the bag from everything else. Ziplock-style bags work, but they’re flimsy; hard plastic or glass seals much better. And do the packing on a clean surface with clean hands, never using the same knife or board that touched regular bread. If the fridge is shared, keep gluten-free items on the top shelf so nothing crumbly falls onto them.

Once you get into the separate-bag habit, it becomes automatic. And honestly, it’s the only way to be sure.